Bulletin of the World Health Organization 2012;90:522-531. doi: 10.2471/BLT.11.092643

Introduction

Cardiovascular diseases (CVDs) are the leading cause of death in the United Kingdom, where coronary heart disease (CHD) and stroke cause 150 000 deaths every year. Of these CVD deaths, more than 40 000 occur prematurely, in people younger than 75 years.1 Apart from smoking, the main risk factors for CVD are elevated blood cholesterol, elevated blood pressure, obesity and diabetes, all related to poor eating habits. According to the United Kingdom’s government report for 2008, poor nutrition causes more than 70 000 preventable premature deaths annually, mainly from CVD.2 A recent paper estimated this figure at 33 000 deaths.3 Regardless, the health effects of poor nutrition pose an enormous economic burden; poor diet alone costs the government of the United Kingdom an annual 6 billion pounds sterling.3

CVD is consistently associated with the so-called “Western” diet, consisting mainly of dairy products, meat and processed foods.2–5 CVD mortality rates are twice as high among segments of society that follow such a diet than among people who eat sensibly.2–4 Salt, sugar, saturated fat and trans fats are harmful when consumed in excess; conversely, fruit and vegetables (which contain potassium, antioxidants and fibre), polyunsaturated fats (e.g. from sunflower and canola oil), mono-unsaturated fats (e.g. from olive oil), whole grains, pulses, nuts and fish have consistently shown a protective effect against CVD.2–4

In the United Kingdom and the United States of America, processed foods and fast, takeaway foods are the main dietary sources of excess salt, saturated fats, trans fats and excess calories. In 2001 the Food Standards Agency (FSA) of the United Kingdom began working with industry to develop a range of healthy food strategies,5 including voluntary product reformulation, clearer (traffic light) package labelling of nutrient levels and media campaigns. The FSA’s salt strategy helped reduce the average daily salt intake by nearly 1 g between 2001 and 2008 (from 9.5 to 8.6 g, respectively).6 However, outside the United Kingdom stricter regulatory policies have resulted in much greater reductions.7 For instance, between 1979 and 2002 Finland’s daily average salt intake fell from 12 g to 9 g.7

The FSA’s strategy in the United Kingdom also sought to reduce the daily average intake of saturated fat from 13.3% to 11% of total food energy by 2010,5 yet currently the figure stands at 12.8%.6 Finland and Iceland, on the other hand, reduced saturated fat intake by 5% of total energy in one or two decades.4,8 Furthermore, in the traditional Italian and Japanese diets and the successful DASH and OMNI diets, 6% of total energy comes from saturated fats.9

Dietary industrial trans fats, resulting from the partial hydrogenation of vegetable oils, are particularly toxic. By raising serum low-density lipoprotein (LDL or “bad” cholesterol) and reducing high-density lipoprotein (HDL or “good” cholesterol), they substantially increase the risk of CHD and stroke.10 The Government of the United Kingdom currently recommends consuming less than 2% of total energy in the form of trans fats. Average trans fat intake for adults in the United Kingdom reportedly represents only 0.8% of total energy consumption.6,11 However, the true value is probably closer to 1% because routine surveys tend to underestimate consumption outside the home, particularly from fast foods. Furthermore, ethnic minorities, low-income adults and children probably consume substantially more.12 In contrast, Denmark’s 2004 legislative ban eliminated the consumption of dietary industrial trans fats within a year (from a baseline of 4%).13 Currently Austria, Canada, Iceland, Switzerland and several states in the United States are aggressively working to eliminate trans fats.10

Finally, the average quantity of fruit and vegetables eaten daily in the United Kingdom has levelled at about 245 g since 2003.6 This is much lower than the pragmatic target of 400 g (five portions) and less than half of the 600 g per day already achieved in much of France, Greece and Italy and now recommended for the entire European Union.14

The FSA reasonably estimated that approximately 7000 CVD deaths would be averted annually if people in the United Kingdom reached the current (modest) dietary targets for saturated fat and trans fats.5,11 However, the potential benefit of more ambitious dietary targets remains unclear. We therefore estimated the potential reduction in CVD mortality achievable in the United Kingdom if stricter, yet feasible food policies were established, as in other countries, to further decrease the intake of salt, saturated fats and trans fats and increase fruit and vegetable consumption.

Methods

The potential decrease in CVD deaths was estimated for two policy scenarios:

conservative: modest dietary improvements, based on assuming that recent trends will continue to 2015, yielding further small reductions in intake (by 0.5% of total energy for trans fat; by 1% of total energy for saturated fat; by 1 g per day for salt) and one additional daily portion of fruit or vegetables;

aggressive: more substantial (but feasible) dietary improvements, as seen elsewhere, yielding larger reductions in intake (by 1% of total energy for trans fat; by 3% of total energy for saturated fat; by 3 g per day for salt) and three additional daily portions of fruit or vegetables.

We developed a spreadsheet model to quantify the deaths potentially averted by adopting healthier food policies. Contemporary data on diet and mortality among adults aged 25 to 84 years in the United Kingdom were obtained from national surveys and official statistics. Potential reductions in CVD mortality were then calculated by synthesizing age-specific population, dietary and mortality data (Appendix A, available at: http://research.ncl.ac.uk/medchamps/assets/WHObulletinUKFoodPolicyOptionsAppend2April12.pdf).1,6

Modelling approach

The CVD deaths averted by each food policy intervention were calculated by multiplying the number of deaths observed in the United Kingdom in 2006 (baseline year) for all age groups between 25 and 84 years by the reduction in the relative risk (RR) of dying from CHD or stroke. The reductions in RR were estimated on the basis of age- and sex-specific values obtained from the largest and most recent meta-analyses and systematic reviews of large controlled trials and observational studies (Appendix B, available at: http://research.ncl.ac.uk/medchamps/assets/WHObulletinUKFoodPolicyOptionsAppend2April12.pdf).

Reduced trans fats

We first assumed, under the conservative policy scenario, that by 2015 the fraction of total energy derived from trans fats would have decreased by an additional 0.5%. We subsequently assumed, under the aggressive policy scenario, that a legislative ban on industrial trans fats would essentially eliminate their intake, as witnessed in Denmark,13 and would further decrease trans fats intake by approximately 1% of total energy.

We then used the RR from the largest meta-analysis to estimate the CVD deaths that would be averted under the aggressive scenario.15 If the 2% total energy derived from industrial trans fats were completely replaced by monounsaturated and polyunsaturated fats, mortality from CHD would drop by approximately 23%.15 Thus, if the total energy derived from trans fats were reduced by 0.5%, the number of CHD deaths would drop by approximately 6%.15

The number of CHD deaths averted under the aggressive scenario was then calculated by multiplying by 0.06 the number of deaths from CHD in the United Kingdom in 2006 in each age group. For example, in 2006 11 947 CHD deaths occurred among men aged 65 to 74 years. The estimated number of CHD deaths averted in this group would thus be approximately:

This process was repeated for all other age groups and for both men and women.

We followed a similar procedure to calculate the number of deaths from stroke potentially averted under the aggressive scenario. If the total energy derived from trans fats were reduced by 0.5%, stroke deaths would be reduced by approximately 3% in both men and women (Appendix B).15

Reduced saturated fats

We assumed that by 2015 the fraction of total energy derived from saturated fats would have been reduced by an additional 1% under the conservative policy scenario, and by an additional 3% under the aggressive policy scenario (from an average of 12.8%5,6 to 9.8%). Using summary estimates from Mozaffarian et al.’s meta-analysis,16 we determined that replacing the 5% of total energy derived from saturated fats with polyunsaturated fats would reduce CHD mortality by approximately 11.5%.16 However, since complete replacement of saturated fats with polyunsaturated fats would be an unrealistic goal, we assumed that only half of the saturated fat would be replaced by polyunsaturated fat and the other half by monounsaturated fat. This would effectively halve the reduction in deaths from both CHD and stroke.16

Reduced salt

We assumed that by 2015 the average salt intake would have decreased by 1 g per day in the conservative scenario and by 3 g per day in the aggressive policy scenario (i.e. from 8.6 to 5.6 g).7 The number of CHD deaths preventable by reducing daily salt intake by 1 g and 3 g was then calculated, as for other nutrients, by multiplying the number of deaths from CHD in the United Kingdom in 2006 by the predicted percentage reduction in CHD deaths. Based on a meta-analysis by Strazzullo et al., we determined that reducing daily salt intake by 5 g (equivalent to 2000 mg less sodium per day) would translate into approximately 17% fewer CHD deaths and approximately 23% fewer stroke deaths annually.17

We followed the same procedure to calculate the potential reduction in deaths from stroke.

Increased fruits and vegetables

We assumed that by 2015 the average intake of fruits and vegetables would have increased by one daily portion of either (from the current average of three portions to four) in the conservative policy scenario and by three portions (i.e. to 500 g or about six portions daily) in the aggressive policy.14

One additional portion a day would reduce CHD deaths by approximately 4% and stroke deaths by approximately 5%, according to Dauchet et al.18,19 To calculate the CHD deaths averted by one and three additional daily portions of fruit and vegetables, we multiplied the number of CHD deaths observed in 2006 by 0.04 and the number of deaths from stroke by 0.05.

Effect of age on mortality

We incorporated age attrition into our model using a method followed by leading cardiovascular epidemiologists.20,21 Specifically, we assumed that the reduction in deaths from CVD associated with a change in the intake of specific macronutrients decreased with age. We modelled this age gradient to mirror the age-specific decreases in the risk of death from CVD associated with both hypertension and elevated total cholesterol.20,21

Cumulative effects: Like other researchers,8,16,17 we assumed that simultaneous improvements in the intake of all macronutrients would have a cumulative rather than a merely additive effect on mortality. For instance, if a reduction of 3 g in daily salt intake had already reduced deaths from CVD by approximately 20%, any additional benefit from reducing trans fats could only act on the residual risk, namely, 80% (i.e. 1 − 0.20).

Sensitivity analyses

All modelling involves uncertainty. We therefore explored the effects of changes in food policy on CVD risk factors and deaths by performing a probabilistic sensitivity analysis. The uncertainty of the hazards ratio and the RR parameters were characterized using a log-normal distribution. We performed Monte Carlo simulations, allowing the parameters based on the effect sizes obtained from the literature to vary stochastically. All calculations were performed separately for men and women and were stratified by age. Results were rounded to the nearest hundred and summarized as medians; 95% CIs for the median were generated using the bootstrap percentile method in Stata version 9 (StataCorp. LP, College Station, United States of America).22

Results

Conservative scenario

In 2006 (the base year), 149 840 CVD deaths occurred in the United Kingdom (94 660 from CHD and 55 180 from stroke). Given population ageing and growth, by 2015 an estimated 168 520 CVD deaths will occur in the United Kingdom (107 140 CHD and 61 380 stroke deaths), representing a rise of approximately 11% if 2006 rates do not change (Appendix C, available at: http://research.ncl.ac.uk/medchamps/assets/WHObulletinUKFoodPolicyOptionsAppend2April12.pdf).

Reducing the total energy from trans fats by 0.5% and from saturated fat by 1%, reducing salt consumption by 1 g per day, and increasing fruit and vegetable intake by 1 portion per day could result in approximately 12 500 fewer CVD deaths (minimum: 5490; maximum: 30 260) (Table 1). This would represent an 8% reduction from the total CVD deaths otherwise expected in 2015 in the United Kingdom.

Approximately 3500 of the 12 500 fewer CVD deaths would result from a decrease of 0.5% in the total energy derived from trans fats; around 4000 from a decrease of 1.0% in the total energy derived from saturated fats; approximately 2300 from a decrease of 1 g in salt consumption, and about 2700 from one additional portion of fruit or vegetables daily. (Table 1)

The 12 500 fewer CVD deaths would comprise approximately 4800 fewer deaths from CHD among men (range: 2050–12 030) and 3500 (range: 1500–8700) fewer among women, and in 1820 fewer deaths from stroke in men (range: 900–4000) and 2400 in women (range: 1050–5500). Approximately 30% of the specific mortality decrease in men and 10% in women would represent reductions in people younger than 65 years (Table 2).

Aggressive scenario

Fig. 1 shows the potential reduction in CVD deaths for each dietary scenario, bounded by minimum and maximum estimates from the sensitivity analysis.

Fig. 1. Estimated annual reductions in deaths from cardiovascular disease (CVD) with modest and more substantial but feasible dietary improvements, United Kingdom

The more substantial decreases in harmful macronutrients and increased consumption of fruit and vegetables could result in approximately 29 900 fewer CVD deaths per year (range: 13 300–74 900) (Table 1 and Table 3). This would represent a reduction in total CVD deaths in the United Kingdom of approximately 20%.

Legislation to effectively eliminate the consumption of trans fats (to reach 0% of total energy) could result in approximately 4700 fewer deaths (range: 2500–8800) per year.

A reduction of 3% in total energy from saturated fats (from 12.8% to 9.8% of total energy) could result in approximately 11 200 fewer deaths (range: 5900–21 600).

A daily reduction of 3 g in salt intake (from 8.6 to 5.6 g per day) might generate approximately 6600 fewer CVD deaths (range: 1700–26 000) per year, while an additional three portions of fruit and vegetables daily could result in approximately 7420 fewer deaths (range: 3160–18 410).

Sensitivity analyses

The relative mortality contributions from these dietary changes remained reasonably consistent in robust sensitivity analyses (Fig. 1 and Table 1).

Discussion

Our conservative estimates suggest that modest dietary improvements in the United Kingdom could avert approximately 12 000 annual deaths from CVD by 2015. However, more substantial improvements could avert about 30 000 CVD deaths annually (still fewer than recorded elsewhere). This would represent a 20% reduction in CVD deaths in the United Kingdom, almost one third of which would have occurred prematurely (

The more substantial improvements would probably require more radical policy interventions. In a recent US study, approximately 40% of all premature CVD deaths (in people less than 70 years of age) might be avoided by optimizing various dietary risk factors.23 The modest discrepancies between this study’s findings and ours could well reflect methodological differences, since Danaei et al. optimistically assumed ideal dietary intake targets that practically eliminated the risk factor.23 Two recent US studies on salt reduction also reported comparable mortality decreases, along with impressive cost savings.22,24 Furthermore, comparable cost savings might be confidently anticipated for all population-wide dietary improvements.25,26

Our estimate of approximately 4700 fewer CVD deaths following trans fat elimination is also reassuringly close to the 7000 quoted in a recent BMJ editorial.10 The benefit for individuals and ethnic groups with insulin resistance may be even greater.10,15 In Denmark, legislation passed in 2004 banning industrial trans fats resulted in a rapid drop to zero consumption.13 After initial opposition, the EU slowly relented and subsequently discussed a ban across Europe.27 Following Denmark, several countries, including Austria, Canada, Iceland and Switzerland (and several US cities and states), have recently taken steps to reduce or ban industrial trans fats in food.10 Canada was the first country to require that the trans fats levels in pre-packaged foods be included on the mandatory nutrition facts table. Though less powerful, labelling regulations inform consumers, motivate industry to reformulate its products and favourably influence social norms. Many manufacturers have now reduced trans fat content.28 In Seattle, a programme to phase out industrial trans fats in fast food outlets encountered surprisingly little opposition from commercial interests; most stakeholders apparently considered it a logical step.29

Diet powerfully contributes to health inequity. Low-income groups, which also suffer the highest burden of CVD and other chronic diseases, have consistently worse diet patterns.30,31 The Government of the United Kingdom has spent over a decade promoting fruit and vegetable consumption, but with frustratingly small improvements.6 Social marketing campaigns and free fruit schemes for schools have clearly not sufficed. Energy-dense, nutrient-poor “junk food” remains cheap and is aggressively marketed,32 whereas fruit and vegetables remain relatively expensive.2,30 Improvements will clearly require additional structural changes.25,32–34

Policy decisions at the European level can powerfully affect food availability and consumption at the national level, both directly and indirectly. The EU Common Agricultural Policy (CAP), which massively influences agriculture and nutrition across Europe, has an annual expenditure of approximately 45 billion euros. This sum represents about 45% of the overall EU budget.27 To deal with the historical threat of food shortages, the CAP has tended to increase the availability of cheap saturated fats while raising the price of and reducing the availability of healthy foods such as fruit and vegetables.14,33,34 CAP reform is urgently needed and should ideally incorporate Finland’s request to the EU for “health in all policies” (including agriculture).

Other effective interventions also exist. Lessons from tobacco control appear surprisingly relevant. The key targets are affordability, accessibility and acceptability.32 If the new government of the United Kingdom is seriously intent upon reducing the double burden of childhood obesity and adult CVD, taxing junk food and using the revenue to subsidize the fresh fruit and vegetable industry would be both feasible and cost-saving, even in an economic recession.10,22,24–26

Our study has several strengths. The methods employed are transparent and easily replicated. Risk factors were treated as continuous rather than categorical variables.35 Diverse but realistic policy scenarios were examined, based upon changes actually observed in other European countries. We also assumed that the benefits would be cumulative rather than additive.36 The estimated 12 000 deaths per year with modest dietary improvements were consistent with FSA estimates based on less rigorous dietary targets.5,11 Our conservative estimates did not include the potential benefits of increasing the intake of nuts, whole grains, fibre and fish; these would have further reduced mortality.37

Our study also has limitations. We did not explicitly model lag times. However, substantial reductions in deaths from CVD following dietary changes can occur very rapidly in randomized cohorts and entire populations.28,38,39 We also assumed that the effects of food policies on dietary intake in the United Kingdom would be quantitatively similar to those in other countries, without explicitly considering political, commercial, cultural and socioeconomic differences or whether other countries’ baseline dietary values were high or low. We also assumed commercial vested interests could be minimised. However, recent notable events include the industry lobbying behind the United Nations’ recent high-level meeting on non-communicable diseases, and the undermining or sabotage of effective interventions such as EU’s front-of-pack food labelling.40,41 The DASH and Omni Heart randomized trials have demonstrated, nonetheless, that individuals can rapidly improve their dietary intake substantially and over the long term, even in the absence of the supportive social environments provided by healthy policies.9

We assumed that trans fats would be replaced by an equal mixture of “good” monounsaturated and polyunsaturated fats, not by “bad” saturated fats (as observed in Canada28). We also assumed that changes in dietary variable would be similar across all age groups. Variance and skew could be assessed in future models, along with compression of morbidity, social stratification and cumulative benefits over a lifetime.

Another assumption was that any effects of dietary changes on mortality would wane with increasing age, as with cholesterol and blood pressure.20,21 Despite this, the greatest benefits were observed in individuals over 75 years of age. Furthermore, dietary changes may be more pronounced in younger people, meaning greater long-term benefits. We did not explicitly consider competing risks. However, healthier food and nutrient policies should also reduce rates of diabetes, common cancers and childhood obesity. Furthermore, we only quantified averted deaths; proportional reductions in non-fatal conditions might reasonably be expected.36 Furthermore, several of our assumptions were tested by means of sensitivity analyses.

Unlike colleagues in the Netherlands and US, we did not model the effect of increasing the intake of nuts, whole grains, sugars, fish or marine omega-3 fatty acids.23,36,37 Promoting United Kingdom fish consumption might pose problems of affordability and sustainability.42 However, even using a complex Markov model, the Dutch results were reassuringly similar: an estimated 21% reduction in cardiovascular events versus our 20%.36 Our calculations only quantified deaths from CVD. Including common cancers might inflate benefits by another fifth, mainly through increased fruit and vegetable intake.3

In conclusion, stricter United Kingdom food policies could substantially and rapidly reduce cardiovascular mortality. Over the past decade, the United Kingdom Government and FSA’s voluntary agreements and partnership with industry have resulted in modest dietary improvements.43 However, the current United Kingdom dietary targets are clearly insufficient longer term. Cosy voluntary agreements with the processed food industry generally fail, much like tobacco policies in previous decades.32,44–46 Conversely, countries with healthier food policies (e.g. Denmark, Finland, Iceland, Norway and Sweden) have seen larger drops in major CVD risk factors and correspondingly bigger mortality reductions.8,43,44,47 However, setting tougher United Kingdom dietary targets will require additional regulatory, legislative and fiscal initiatives: evidence-based policy interventions recommended by the British National Institute for Health and Clinical Excellence (NICE), the World Health Organization (WHO), The World Bank and the United Nations.37 Indeed, both adults and children deserve better protection from the detrimental effects of cheap junk food and sugary drinks.32,40,41,45,46,48,49And a simple first step could be to eliminate industrial trans fats, as done successfully in Denmark and elsewhere.13

Funding:

MOF received funding from the UK Medical Research Council and from the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement n°223075 – the MedCHAMPS project. No funding body had any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests:

SC was the vice-chair of the NICE PDG on CVD prevention in populations (2009–2010), and is a member of the British Heart Foundation (BHF) prevention and care committee. However, our recommendations do not necessarily reflect the views of NICE or the BHF.